Sleep Growth Curves in the Preschool Years as Predictors of Early Academic Performance

• In Event: 2-089 - Sleep and Cognition from Infancy to Middle Childhood: The Role of Socioeconomic Factors

Integrative Statement

Cognition is one of the aspects of human functioning that shows the clearest connections to sleep among adults (Walker, 2009). Given that the brain is considerably more plastic during early childhood, which also constitutes a time of intense learning, one might expect the links between sleep and cognition to be particularly pronounced early in life; there is, however, much less research with young children than adults.
During the preschool years, sleep undergoes important developments, notably an increase in sleep quality (e.g., fewer night awakenings) and a gradual decrease in sleep duration. Thus, perhaps some of the most meaningful aspects of preschool sleep pertain to its developmental trajectories; however, we are aware of no studies that have used developmental patterns of sleep in the preschool years as predictors of child cognition. This was the primary aim of this study. A secondary aim was to consider these predictive links in the family context, and investigate whether they differed in higher- and lower-SES families, as often observed in studies of child sleep and cognition (Buckhalt et al., 2007).
100 children wore an actigraph monitor (Mini-Mitter® Actiwatch) for 3 consecutive days at 2, 3, and 4 years of age. Actigraphy data were used to derive average sleep duration and efficiency (an index of sleep quality) over the 3-day period at each age. When children were in the first grade of elementary school (M = 7.1 years), their performance in both reading and mathematics was assessed with the Weschler Individual Achievement Test. To control for initial cognitive functioning, expressive language was assessed at age 2.
Growth curves of both sleep duration and efficiency between ages 2 and 4 were fitted in Mplus. The resulting intercepts and slopes for duration and efficiency were extracted for each child, and then used to predict reading and maths performance in SPSS.
The results revealed that the intercept and slope of sleep duration, but not efficiency, were predictive of academic performance: after accounting for child sex and cognitive functioning at age 2, children who slept longer at age 2 showed better performance in both reading ( = .32, p = .004) and maths ( = .27, p = .015) in Grade 1. Concerning the slope, children whose sleep duration decreased more rapidly between ages 2 and 4 showed better performance in reading ( = .31, p = .005) and maths ( = .27, p = .015). These links were especially clear in relatively higher-SES families, but systematically non-significant in lower-SES families.
These findings suggest that children whose sleep duration is initially higher and then more rapidly follows the expected age-related declining trajectory subsequently perform better in basic subjects when they enter school. Hence, developmental changes in sleep during the preschool years may be particularly meaningful for cognitive development and learning. The results also suggest that these effects are specific to higher-SES families, perhaps because in lower-SES families, other factors (parenting stress, household chaos, etc.) interfere with child learning and override the otherwise positive effects of optimal sleep patterns.

Authors

• Catherine Cimon-Paquet, University of Montreal
  Presenting Author

• Annie Bernier, University of Montreal
  Non-Presenting Author

• Émilie Tétreault, University of Montreal
  Non-Presenting Author

• Célia Matte-Gagné, Laval University
  Non-Presenting Author